Chrome turned 21 last week, and in that new version, Google's made playing Flash videos in its browser even safer… for Windows users, anyway. This latest release puts Adobe's Flash Player plug-in for Windows in a sandbox, much as Chrome 20 did for Linux. This sandbox is "as strong" as Chrome's extremely robust native version — even in Windows XP — which means that Flash-borne malware can't hurt Microsofties. Securing the Flash Player plug-in …